Income tax fundamentals: rates, bands, and allowances
Start with the shape of the calculation, because every R03 income tax question is a walk through the same four stages. Stage one: sort the income into its three categories — non-savings (salary, pensions, rental), savings (interest), dividends — because each category has its own rates and its own 0% amounts. Stage two: apply the £12,570 personal allowance. This is a true DEDUCTION: income it covers leaves the calculation entirely. Hold onto that word, because the next stage uses a different mechanism and the exam deliberately tests whether you can tell them apart. Stage three: stack the taxable income through the bands in the fixed statutory order — non-savings first, then savings, then dividends. The order is not a choice, and it matters because whatever goes first eats the £37,700 basic-rate band, pushing later categories toward higher rates. Stage four: within that stack, apply the 0% amounts — the personal savings allowance and the £500 dividend allowance. Despite their names, these are NIL-RATE BANDS, not deductions and not exemptions: income inside them is taxed at 0% but still sits in the stack, still uses up band capacity, and still counts toward every income test (the £100,000 taper, the PSA tier itself). Only genuinely EXEMPT income — an ISA's interest or dividends — stays out of the calculation altogether. That three-way distinction (deduction / nil-rate band / exempt) is the single most productive fact in this lesson: a question that says 'no tax was payable on the interest' has NOT told you the interest is invisible. Two refinements complete the picture. The £5,000 starting rate for savings sits underneath the basic-rate band and is eroded pound-for-pound by taxable non-savings income, so anyone with a full salary loses it before it does anything. And above £100,000 of adjusted net income the personal allowance tapers away at £1 per £2 — adjusted net income meaning income from EVERY category, including amounts sitting at 0% inside the allowances. Scottish taxpayers change one thing only: their non-savings income uses the six Scottish bands; savings and dividends stay on the UK bands whoever the taxpayer is.
- Salary £30,000: taxable after the personal allowance
- 30,000 - 12,570 = £17,430
- Non-savings tax at the basic rate
- 17,430 * 0.2 = £3,486
- Interest £1,500: covered by the basic-rate PSA first
- 1,500 - 1,000 = £500
- Remaining interest at the basic rate
- 500 * 0.2 = £100
- Dividends £2,000: dividend allowance comes off the top
- 2,000 - 500 = £1,500
- Remaining dividends at the basic dividend rate
- 1,500 * 0.0875 = £131.25
- Total income tax
- 3,486 + 100 + 131.25 = £3,717.25
Notice what the 0% amounts did NOT do: the PSA-covered interest (£1,000) and the allowance-covered dividends (£500) are still in the band stack and still part of total income — they were taxed at 0%, not removed. If this client instead held the interest and dividends inside an ISA, those amounts would be genuinely exempt: out of the stack, out of every test, never reported.